Even French astronaut Thomas Pesquet, who just returned from his mission on the International Space Station, said he would love to explore Mars one day and that "it will be an incredible adventure".

Visiting Paris during the "Hello Tomorrow" conference, Laura Kerber, researcher at NASA's "Jet Propulsion Laboratory" and geomorphology specialist for Mars, told Business Insider France why Elon Musk and his project on Mars is important for space exploration, the obstacles he has to overcome to get to Mars, and how we could live in the decades to come.

Business Insider France: Elon Musk intends to colonize Mars with a million people within 50 years, using a reusable rocket. Is his project feasible?

Laura Kerber, NASA researcher: Our relationship with Elon Musk is very positive, as he builds new great rockets and lowers their price. It's something very exciting. His project has a very tight schedule, which is interesting because it inspires and pushes others to move forward.

What does it matter if people say, 'Elon Musk has promised something, but he will only do it after three years'. It's better than never. He has promised to achieve something ambitious and, even if he is 20 years late, it will probably be 30 years earlier than everyone else.

I cannot guess his intentions, but the simple fact of having an ambitious project like his is something positive for humanity. In the distant future, space colonization will not be a project of NASA or ESA, but a project of humanity.

The rocket imagined by SpaceX to go on Mars is supposed to be able also to supply the ISS. SpaceX SpaceX BI France: What are the main obstacles that have to be overcome to go to Mars, without necessarily talking about living there?

Kerber: There are technological challenges to overcome even though most technologies are nearing completion. The biggest challenges are radiation protection, the landing of heavy objects on the Martian ground, which seems rather difficult, and the construction of rockets large enough to carry significant payloads.

People are working on all these things right now. But all these challenges cost money and it is valuable to work in several countries. This is the case today. At NASA, we work a lot with Jaxa, Israel, ESA and other space agencies.

I also think that space agencies are challenging each other to make progress.

BI France: The United Arab Emirates has imagined the first habitable city on Mars by 2117. One can see dwellings in the form of domes in particular. That's what awaits us?

Kerber: There is a lot of work on the type of housing we could have on Mars. First, they must be pressurized to protect you from the Martian atmosphere and they must have walls thick enough for you protect against radiation. If you build your walls with normal protective materials, you will need several meters of wall thickness to protect yourself.

So, some have imagined houses in the shape of little igloo, on which you will pile up Martian dust. Others think they can live in an underground tunnel.

I proposed another idea in 2015: build a house on the cliff because there are big cliffs on Mars. You have some examples of this type of housing in the Cappadocia region of Turkey, where the first Christians hid [to avoid persecution]. About 8000 people could hide there.

An illustration of the inhabited city on Mars imagined by the United Arab Emirates. Dubai Media Office It's fun to use a centuries-old model of housing that dates back centuries to a futuristic project like going to Mars that requires state-of-the-art technology.

I think that life on Mars will be something at the forefront of technology but also very primitive. A bit like the Apollo mission astronauts. When they went to the moon for the first time, they did not have toilets. They went "to the bathroom" with a bag or a bottle. It was a very primitive way of life.

It will be the same for Mars. If you go to another planet, you will probably return to a primitive civilization ... maybe even live in a cave. Especially since a cave is a great place when you think about it: same temperature all year long, you are protected from everything that can come from outside.

So living on Mars is both living in the future and returning to the past. Because it will be tough enough to live in space or live on Mars.

BI France: So, will life on Mars will be difficult? Will there be anything glamorous?

Kerber: Not at first, but eventually it could become so. Initially, it will be really difficult, like the first astronauts who lived aboard the International Space Station (ISS). You will have to eat food that may not be very tasty and give up some of your privacy. Your body will also endure difficult things, you will have to exercise more than three times a day just to keep your muscles and bones fit.

The fact that the planet is completely empty will be interesting for us. Because here we have all these laws and rules to respect. There, you could invent a new company from scratch.

And there are so many unexplored wilds on Mars and so few on Earth. Explorers in the soul will spend a wonderful time on Mars, not to mention geologists like me.

Whenever there are rocks and I see grass on it, I say to myself, 'Oh, take away all this biological stuff, I want to see the beautiful stones below'. And on Mars, I will not have this problem. Finally, you also have two moons, one of which passes over your head several times a day.

Elon Musk speaks at the International Astronautical Congress on September 29, 2017 in Adelaide, Australia. Musk detailed the long-term technical challenges that need to be solved in order to support the creation of a permanent, self-sustaining human presence on Mars. Mark Brake/Stringer/Getty Images BI France: What is the thing that still surprises you now about Mars?

Kerber: Every time we look at Mars, we see the planet under a certain resolution of images and we say 'it's good, I think I understood what is happening there'. Then, a new generation of satellites arrives and you take new pictures with better resolution and there you say to yourself 'I have no idea what is actually happening'.

People might say that we've known Mars for a while and we've raised the mystery about all the major issues, but that's not the case.

Whenever we observe Mars, something even more confusing appears, something that does not agree with the theory we had before.

The most romantic thing about Mars, when you examine the past of this planet, are all these rivers, lakes and deltas. All these things suggest that Mars was a place where we could find water in abundance, but something happened and since then it has become a dry and cold desert, a kind of polar desert. How is it that a planet evolves like that? I think it's important for us to find out.

Hello Tomorow/YouTubeBI France: It is important to know because it is related to the history of the Earth?

Kerber: Venus is a planet that is about the same size as Earth and that once had all the things the Earth currently has. But something happened to Venus. Maybe she's a little too close to the sun.

We know that there was an ocean that evaporated completely. Since then, Venus has turned into a super hot planet, where the surface is so hot that everything melts, with an overwhelming pressure of 93 bar.

The Earth has the same amount of CO2 as Venus, but this CO2 is hidden in the rocks that are on its surface so it is not free in the air. The Earth could have suffered the same fate as Venus, but she did not do it.

On the other hand, you also have Mars, which was once a nice place, but was perhaps too far from the sun and has since become a cold planet. The Earth went through similar periods when its surface was completely covered with ice, but something freed it from this cold and it became a hot land again.

The Earth is such a complex planet. It is one of the most complicated systems we know. If you look at Mars or Venus, which are simplified versions of the Earth, you will surely be more likely to separate the different processes and know what their respective effects were.